Hollow fiber device for removing waste material in the blood and a process of manufacture thereof

A method of manufacturing a medical hollow fiber device for removing waste material in the blood, including a housing having two ends, a plurality of bundles of hollow fiber membranes having an interior, an exterior and open end portions, the bundles of membranes provided in the housing for moving the waste material in the blood from the interior of the membrane to the exterior thereof, and two opposing closures which receive the open end portions of the fiber membranes, the method comprising the steps of:

• providing a housing;
• coiling the hollow fiber membranes into loops;
• providing bundles of looped hollow fiber membranes and placing them into the housing;
• filling a liquid into the entire interior of the hollow fiber membranes;
• closing both ends of the housing with caps;
• supplying viscous potting material into the housing at the end portions of the hollow fiber membranes while keeping the end portions of the hollow fiber membranes unrestrained in a transverse direction by any additional member;
• applying a centrifugal force to the housing whereby the potting material penetrates between the end portion and exerts an outside pressure on the membranes, and whereby the liquid in the membranes moves toward both ends of the housing and exerts an inside pressure acting against the outside pressure of the potting material until the potting material solidifies, so that the inside pressure in the end portions of the hollow fiber membranes overcomes the outside pressure of the potting material before its solidification because the ends of the hollow fiber membranes are unrestrained by any additional member, thereby providing a uniformly increasing circular cross-section in the end portions of the hollow fiber membranes to effect smooth fluid flow, the liquid also serving to keep potting material out of the end portions of the hollow fiber membranes;
• cutting the opposing closures after the potting material has solidified to make said end portions open;
• and
• providing openings for the blood running at the ends of the housing.